A known problem for electric camshaft phasers is “drift” of the rotor relative to the stator after engine shut-down. For example, immediately or shortly after engine shutdown, torque may be transmitted to the rotor in sufficient magnitude to cause the electric camshaft phaser to drift, or shift away from an intended control angle of the rotor with respect to the stator due to a lack of inherent resisting torque in the electric camshaft phaser or inherent friction associated with the electric motor and gearbox combination in the electric camshaft phaser. The rotational direction and magnitude of the residual torque and inherent friction are unpredictable; therefore, the rotation and eventual final control angle of the rotor due to the residual torque from the camshaft or the inherent friction cannot be predicted.
FIG. 12 is prior art taken from FIG. 13 of PCT Patent Application PCT/US2015/036928 (the '928 application). Electric camshaft phaser 38 includes portion 46 in rotational communication with a crankshaft, portion 48 attached to a camshaft and in rotational communication with portion 46, and portion 50 operatively attached to an actuator and in rotational communication with portion 48. Phaser 38 also includes locks 54 (in the form of lever springs) with ends 92 connected to portion 50, and ends 94 with portions 98 for releasably engaging receivers 52 in portion 48. Locks 54 can be used to lock portion 50 to portion 48. During operation of phaser 38 with portions 98 not engaged with receivers 54, portions 98 are in constant contact with portion 48 resulting in drag on the operation of the actuator and constant flexing of the lever springs, which reduces service life of the lever springs.